INFO: task syz-executor4:4841 blocked for more than 120 seconds.
      Not tainted 4.4.107-g610c835 #12
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4   D ffff8801d4d574d8 26552  4841   3566 0x00000004
 ffff8801d4d574d8 ffff8801d4d57478 ffffffff837732c8 ffff8801db21ef80
 ffff8801d4d574d0 ffffffff811a2100 ffff8801db21f878 ffff8801db21f8a0
 ffff8801db21ef98 ffff8800b1752f80 ffff8801d4d90000 ffff8801d4d50000
Call Trace:
 [<ffffffff83765d3a>] schedule+0x9a/0x1c0 kernel/sched/core.c:3351
 [<ffffffff83770fd1>] schedule_timeout+0x3a1/0x970 kernel/time/timer.c:1508
 [<ffffffff83763cbe>] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:4932
 [<ffffffff83766feb>] io_schedule include/linux/sched.h:447 [inline]
 [<ffffffff83766feb>] bit_wait_io+0x1b/0xc0 kernel/sched/wait.c:595
 [<ffffffff83766b2f>] __wait_on_bit_lock+0x8f/0x140 kernel/sched/wait.c:434
 [<ffffffff8141a9cd>] __lock_page+0x18d/0x1f0 mm/filemap.c:888
 [<ffffffff815b8620>] lock_page include/linux/pagemap.h:458 [inline]
 [<ffffffff815b8620>] __generic_file_splice_read+0x730/0xb00 fs/splice.c:412
 [<ffffffff815b8ad2>] generic_file_splice_read+0xe2/0x1c0 fs/splice.c:542
 [<ffffffff815b4dd5>] do_splice_to+0xf5/0x140 fs/splice.c:1154
 [<ffffffff815b5070>] splice_direct_to_actor+0x250/0x830 fs/splice.c:1226
 [<ffffffff815b57f7>] do_splice_direct+0x1a7/0x270 fs/splice.c:1337
 [<ffffffff8151e99c>] do_sendfile+0x54c/0xd30 fs/read_write.c:1227
 [<ffffffff81520a13>] SYSC_sendfile64 fs/read_write.c:1282 [inline]
 [<ffffffff81520a13>] SyS_sendfile64+0xc3/0x150 fs/read_write.c:1274
 [<ffffffff83773d36>] entry_SYSCALL_64_fastpath+0x16/0x76
1 lock held by syz-executor4/4841:
 #0:  (sb_writers#6){.+.+.+}, at: [<ffffffff8151ed34>] file_start_write include/linux/fs.h:2521 [inline]
 #0:  (sb_writers#6){.+.+.+}, at: [<ffffffff8151ed34>] do_sendfile+0x8e4/0xd30 fs/read_write.c:1226
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 485 Comm: khungtaskd Not tainted 4.4.107-g610c835 #12
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bb2aaf80 task.stack: ffff8800bba18000
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bba1fcb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bba1fce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426abe0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efe1286f000 CR3: 00000001d4b64000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426abe0 ffffffff847e8600 00000000000194a0 0000000000000040
 dffffc0000000000 ffff8800bba1fd00 ffffffff810b8e1b ffffffff839f53e0
 0000000000000003 ffff8800bba1fd60 ffffffff81d0f4d7 ffffffff81417c73
Call Trace:
 [<ffffffff810b8e1b>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81d0f4d7>] nmi_trigger_all_cpu_backtrace+0x4a7/0x550 lib/nmi_backtrace.c:85
 [<ffffffff810b8eb4>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff81365a7a>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff81365a7a>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81365a7a>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81365a7a>] watchdog+0x6fa/0xae0 kernel/hung_task.c:238
 [<ffffffff8118dea8>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff837740ef>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468
Code: b3 5f ff f6 c4 10 75 e1 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 74 1a e8 3b 09 17 00 4c 89 e7 57 9d 0f 1f 
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.107-g610c835 #12
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801da2997c0 task.stack: ffff8801da2a8000
RIP: 0010:[<ffffffff810cf516>]  [<ffffffff810cf516>] native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:49
RSP: 0018:ffff8801da2afd78  EFLAGS: 00000246
RAX: 0000000000000007 RBX: ffffffff847d6708 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8801da29a02c
RBP: ffff8801da2afd78 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efe1279b5bb CR3: 00000001d4b64000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801da2afdb0 ffffffff81027d75 ffff8801da2b0000 ffffffff847d6708
 0000000000000000 0000000000000000 dffffc0000000000 ffff8801da2afdc0
 ffffffff810292ea ffff8801da2afdd8 ffffffff8121e338 ffff8801da2b0000
Call Trace:
 [<ffffffff81027d75>] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline]
 [<ffffffff81027d75>] default_idle+0x55/0x3c0 arch/x86/kernel/process.c:291
 [<ffffffff810292ea>] arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:282
 [<ffffffff8121e338>] default_idle_call+0x48/0x70 kernel/sched/idle.c:93
 [<ffffffff8121ea45>] cpuidle_idle_call kernel/sched/idle.c:157 [inline]
 [<ffffffff8121ea45>] cpu_idle_loop kernel/sched/idle.c:253 [inline]
 [<ffffffff8121ea45>] cpu_startup_entry+0x605/0x820 kernel/sched/idle.c:301
 [<ffffffff810ad2e4>] start_secondary+0x304/0x3e0 arch/x86/kernel/smpboot.c:251
Code: 00 00 00 00 00 55 48 89 e5 fa 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 f4 5d c3 66 0f 1f 84